airsense 10 OVERpressure!

[justMongo]

Soooo...(set on auto 5-20)if the machine decides I need a 14.6 flow why once i'm awake doesn't it go back to a more normal 5ish flow??? That's why they gave me a different unit (saying it should react faster)

An auto will tend to go up and down as needed all night. Just waking up will not lower the pressure it's at. Shut off and restart will. Some machines aggressively increase pressure to head off impending apnea -- then are slow to retreat.

Running from 5-10 likely will not give you adequate therapy.
On Tuesday, do not be surprised if you get an attitude from the Lincare tech for changing presssure.

Is it normal to use a full humidifier tank in one night (set on 4)???

Depends on the relative humidity of your room air. It's not uncommon for it to use nearly all the water.

[PaytonA]

Depends on the relative humidity of your room air. It's not uncommon for it to use nearly all the water.

A fact that Mongo and I are very familiar with.

[vsheline]

I will talk to the tech about the benefit of the Her unit.

Soooo...(set on auto 5-20)if the machine decides I need a 14.6 flow why once i'm awake doesn't it go back to a more normal 5ish flow??? That's why they gave me a different unit (saying it should react faster)

Is it normal to use a full humidifier tank in one night (set on 4)???

Hi Bill,

1. There are several threads on the new AirSense 10 units. If you read a few of them you may learn a few things about the For Her model which the tech doesn't know yet.

2. Although the ResMed Auto-adjusting machines (like yours) increase pressure fairly quickly, between pressure increases the pressure is always decaying very gradually, very slowly trying to get back to a low pressure target (which is the Minimum Pressure setting). This is called fast attack with slow exponential decay.

Mathematically, the rate of decay has a Time Constant, and the Time Constant for ResMed APAP machines is 20 minutes (and this has been unchanged for many years). This means that (unless some "event" occurs which causes the pressure to be raised again) during the first minute (which is 5% of one Time Constant) the pressure will have decayed about 5% of the way toward the Min Pressure setting. For example, if the current pressure is 15 and the Min Pressure setting is 5 (which is a difference of 10) then during the first minute the pressure would have decayed about 5% of 10, which is 0.5, which means the pressure would have decayed to about 14.5.

That's not much of a change during the first minute. It would take about 14 minutes for the pressure to decay halfway toward the Min Pressure setting.

3. When a high amount of leaking is occurring the water in the humidifier will get used up quickly, because of all the extra air passing through the humidifier. Even without high leaks, the water gets used up more quickly whenever the pressure is high because of the higher airflow through the mask vent holes.

Take care,
--- Vaughn

[Lambsydoats]

Smart start not recommended for full face mask due to the anti-asphyxia valve.
Might even be greyed out in menu when set for FFM.

Hmmm. I've used smart start from the beginning (November 10) with a FFM and have had no problems with it...FWIW

Lamb

[xzostd]

Soooo...(set on auto 5-20)if the machine decides I need a 14.6 flow why once i'm awake doesn't it go back to a more normal 5ish flow??? That's why they gave me a different unit (saying it should react faster)

An auto will tend to go up and down as needed all night. Just waking up will not lower the pressure it's at. Shut off and restart will. Some machines aggressively increase pressure to head off impending apnea -- then are slow to retreat.

Running from 5-10 likely will not give you adequate therapy.
On Tuesday, do not be surprised if you get an attitude from the Lincare tech for changing presssure.

Is it normal to use a full humidifier tank in one night (set on 4)???

Depends on the relative humidity of your room air. It's not uncommon for it to use nearly all the water.

I will talk to the tech about the benefit of the Her unit.

Soooo...(set on auto 5-20)if the machine decides I need a 14.6 flow why once i'm awake doesn't it go back to a more normal 5ish flow??? That's why they gave me a different unit (saying it should react faster)

Is it normal to use a full humidifier tank in one night (set on 4)???

Hi Bill,

1. There are several threads on the new AirSense 10 units. If you read a few of them you may learn a few things about the For Her model which the tech doesn't know yet.

2. Although the ResMed Auto-adjusting machines (like yours) increase pressure fairly quickly, between pressure increases the pressure is always decaying very gradually, very slowly trying to get back to a low pressure target (which is the Minimum Pressure setting). This is called fast attack with slow exponential decay.

Mathematically, the rate of decay is called the Time Constant, and the Time Constant for ResMed APAP machines is 20 minutes (and this has been unchanged for many years). This means that (unless some "event" occurs which causes the pressure to be raised again) during the first minute (which is 5% of one Time Constant) the pressure will have decayed about 5% of the way toward the Min Pressure setting. For example, if the current pressure is 15 and the Min Pressure setting is 5 (which is a difference of 10) then during the first minute the pressure would have decayed about 5% of 10, which is 0.5, which means the pressure would have decayed to about 14.5.

That's not much of a change during the first minute. It would take about 14 minutes for the pressure to decay halfway toward the Min Pressure setting.

3. When a high amount of leaking is occurring the water in the humidifier will get used up quickly, because of all the extra air passing through the humidifier. Even without high leaks, the water gets used up more quickly whenever the pressure is high because of the higher airflow through the mask vent holes.

Take care,
--- Vaughn

Excellent info ....now if the tech knew how my unit actually worked (time constant) she would not have replaced it based on the unit appearing to work as designed. I can handle any attitude that the tech may deliver

[kmar92]

I know that Resmed deny that they have changed algorithms with the A10 but increasingly I see these reports of A10's aggressively raising pressure in response to flow limitations, events, etc and being very slow to lower the pressure resulting in A10's hitting the max pressure and staying there?

[vsheline]

I know that Resmed deny that they have changed algorithms with the A10 but increasingly I see these reports of A10's aggressively raising pressure in response to flow limitations, events, etc and being very slow to lower the pressure resulting in A10's hitting the max pressure and staying there?

Hi kmar92,

As of now, the only person I remember reporting that he has tried both machines and has found that the A10 raises the pressure more aggressively, is Zonk, and I don't know how many times Zonk has switched back and forth (one night on S9, the next night on A10, repeatedly) to see how repeatable this was in his case.

To see if the A10 in standard AutoSet therapy mode really does behave more aggressively than the S9 AutoSet, I think what would be needed is for a couple dozen patients to switch repeatedly back and forth between the two machines, to see if statistically significant differences really do exist.

The rate of pressure decay is purely software, is completely determined by the software algorithm and therefore is probably unchanged, since ResMed has said that the software algorithm is unchanged for the standard AutoSet therapy mode.

The rate of pressure increase, however, would be affected by software and by hardware sensitivity. If the sensors are more sensitive or better calibrated on the new A10 units, perhaps that may result unintentionally in a more aggressive response.

Also, it may be possible that the main treatment algorithm is unchanged but that some minor aspect of the software has been improved (like perhaps how well the software detects/calculates how much Flow Limitation is occurring, or how well it detects/calculates and compensates for Leak) which has indirectly increased the machine's sensitivity to Flow Limitation, making the machine raise pressure more proactively. Or maybe a software bug was eliminated or introduced, affecting this.

[PsychoMike]

Hey XZ,

Yeah, the ResMed machines don't come with a feature like the F&P Icons...the Icon machines have "SenseAwake" which chops the pressure back hard when it believes you are awake.

The AutoSets do, however, raise the pressure fairly quickly in response to events....and reduce it slower. It sounds like you machine has been reacting to apnea events and it gets to a point where you wake up due to leaks / pressure that you're not accustomed to yet.

I agree that using the mask fit is a better idea than the starting pressure...I've fit mine that way (max pressure / mask fit) and backed off the strap tension a bit (my max pressure these days is only about 12, even though I have my machine able to use up to 17).

I suspect (and with sleephead or similar you'd be able to look...just don't forget to lock the SD card before you put it in your computer and unlock it again before putting it back in your CPAP) that you're likely getting events when you it a certain sleep stage (say a little over an hour in) and that's where the pressure is getting increased. With it being a new thing for you, the additional pressure and leaks are waking you up.

Hang in there....hopefully your tech won't give you tons of attitude and between them (though I don't put much faith in them these days) and what you learn for yourself, you'll get good and effective treatment soon that will have you sleeping like the proverbial baby

[zonk]

Hi kmar92,

As of now, the only person I remember reporting that he has tried both machines and has found that the A10 raises the pressure more aggressively, is Zonk, and I don't know how many times Zonk has switched back and forth (one night on S9, the next night on A10, repeatedly) to see how repeatable this was in his case.

zonk is not the only one, actually, does not matter to me one bit if I was the only one, I don't swim with tide or follow the crowd ...
there is the right way, the wrong way and zonk way ...

At least 3 or 4 people including the OP have reported something similar. For every person who report a particular problem, probably many more don't report the problem for a various reasons ... they have not tried other machine to compare with, they don't have a clue, intimated or scared to open their mouth, so they just smile and play pretend ... and reply .. fine, thank you

Just like dining in a fine restaurant, not everyone complain about receiving bad meal or service, some out of politeness and not to make a fuss, they just pay the bill and never to come back and some complain to the head waiter and have the problem sorted out and or even better, the management offer them the meal and wine free on the house as token of appreciation

Last night pressure was at or below the maximum 13, FL could sent the pressure higher but I don't allow it and not necessary as everything else looks good, slept over 7 hours non-stop, AHI 0.1 (1 hypopnea all night) ... this is a good night for me

Its been said too often, increase the maximum pressure and let the machine do its thing, respectfully - I happen to disagree ...
the proof of the pudding is in the eating

[Mr. Van Winkle]

Thanks for all the info. many different very helpful ideas. You've all helped me increase my knowledge 100% in only 24 hrs. !!!

If I understand correctly I can download a program such as sleepyhead and it will read the data card??? (in a user friendly way?)
Which program is better for a new cpap user. (just barely computer literate !!!)

I did reset my auto settings from 5 -20 to 5-10 no ramping and had a much better night. Leaving this way until Tues. when I have a appointment with the Lincare tech, but will turn on smart start for tonight

I will talk to the tech about the benefit of the Her unit.

Soooo...(set on auto 5-20)if the machine decides I need a 14.6 flow why once i'm awake doesn't it go back to a more normal 5ish flow??? That's why they gave me a different unit (saying it should react faster)

Is it normal to use a full humidifier tank in one night (set on 4)???
Bill

Bill,
I'm also very new to this hose head thing, But it really sounds like a real mask leaking problem, when you use your water up at a low temp. it doesn't sound right, Mine is at 5 and I'm always dumping some out , I wake up now without a concrete mouth .
Before you give up on the machine try a different mask, I was having trouble waking up in the earlier morning when my pressure were high feeling like I could breath, my mask wouldn't let me exhale properly. I was always fiddling with my mask to get a good seal .
I'm now using a different mask and wow what a difference , I have just had 3 night's in a row that were awesome! (hope I didn't jinx myself). Anyway I thought for sure it was the Airsense machine, nope it was the mask. I really like my N10 mask but I think it has a Issue that I'll look into later but the new F&P Eson is working great!

Good luck you will get it resolved!

Mr. Van Winkle